As is well known in the art, a conventional wheelchair has two large, rear wheels on either side of a seat while small caster wheels are positioned on either side of a footrest. Such a wheelchair is generally propelled either by a person, such as an attendant, pushing from behind, or by the occupant pushing against the large, rear wheels. In order to facilitate occupant propulsion of the wheelchair, many conventional wheelchairs have rims which project outward from the rear wheels for grasping and pushing. Although viable in many types of environments, such conventional wheelchairs have several disadvantages. First, the use of conventional wheelchairs for an extended period of time can cause wrist and rotor cuff injuries to the occupant due to the repetitive need to angle the wrist and then push to provide forward locomotion. Further, conventional wheelchairs are typically braked by the occupant grabbing and holding the wheel or the turning rim attached to the wheel. When the wheel is turning at a rapid rate, grabbing the wheel may cause friction burns and grabbing the wheel rim may cause injury to the hand.
In order to overcome the problems described above, occupant propelled wheelchairs which use a rowing mechanism to provide propulsion have been proposed. An example is shown in U.S. Pat. No. 4,811,964 to Horn which teaches a wheelchair with a single reciprocating rowing lever in which power strokes are developed in both the pull and the push direction.
Although wheelchairs which use a rowing mechanism, such as the patent to Horn, provide a good means of locomotion, the locomotion means is still limited to a single wheelchair. Wheelchairs can be a very expensive purchase. The cost of a wheelchair can prevent some of those in need of a wheelchair from having access to a means of locomotion. As the propulsion means with its levers and gears is often the most expensive component of a wheelchair system, it is desirable to have a propulsion means which is capable of providing locomotion to more than one wheelchair. U.S. design Pat. No. 294,476 to Michel et al. teaches a modular wheelchair base without propulsion means. However, in order to provide the occupant with independence, it is desirable to have a wheelchair base which allows for occupant propulsion.
U.S. Pat. No. 838,228 to Williams discloses a chair truck and self contained propelling means therefor. The chair truck disclosed in Williams is adapted for carrying various sizes of rocking chairs and is provided with means controlled by the occupant whereby the chair may be moved about in any direction. In order to best provide locomotion to more than one wheelchair it is desirable to have a propulsion means which can slip into and out of engagement with a support means. A chair is then releasably engaged with the support means. It is further desirable that the support means be mobile so that the support means with a chair mounted thereon can be pushed by an attendant when the propulsion means is not engaged with the support means.
The wheelchair of the present invention includes three component parts: a propulsion means, a mobile support means provided with means for receiving the legs of a chair, and a chair. The propulsion means is removably engaged with the support means by sliding the propulsion means into the support means. A chair is then engaged with the support means by inserting the chair legs into the means for receiving the chair legs on the support. The means located on the support for receiving chair legs can be varied to accommodate a variety of chair types.